[DevTools] Touch emulation in content.

content/browser/renderer_host/input/touch_emulator.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EMULATOR_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EMULATOR_H_
+
+#include "content/common/content_export.h"
+#include "content/common/cursors/webcursor.h"
+#include "content/port/common/input_event_ack_state.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+#include "ui/events/gesture_detection/filtered_gesture_provider.h"
+
+namespace content {
+struct NativeWebKeyboardEvent;
+class RenderWidgetHostImpl;
+
+// Emulates touch input with mouse and keyboard.
+class CONTENT_EXPORT TouchEmulator : public ui::GestureProviderClient {
+ public:
+  explicit TouchEmulator(RenderWidgetHostImpl* host);

[jdduke (slow), 2014/04/04 16:21:11]

Other than the cursor creation and the RenderWidgetHostImpl dependency, this is
very close to being quite easy to unit test.  I'd feel a lot more comfortable if
we had a few very basic tests where we feed in some mouse events and check the
output, toggle the shift modifier, etc...  Doesn't have to be anything too
complicated, more as a sanity check that can be fleshed out.

Perhaps add a TouchEmulatorClient with the RWHI dispatch methods that are
currently used?  If the WebCursor creation from resource is a problem, we could
just provide it as an argument in the constructor?

[dgozman, 2014/04/07 16:54:55]

Done.

+  virtual ~TouchEmulator();
+
+  // Returns |true| if the event was consumed.
+  // TODO(dgozman): maybe pass latency info together with events.

[jdduke (slow), 2014/04/04 16:11:28]

A new LatencyInfo will be generated for the touch, and for now it's important
that the touch type is used when the LatencyInfo is initialized.

However, we may want to pass the touch's LatencyInfo into |HandleTouchEventAck|,
and use that to populate the gesture LatencyInfo... miletus@, what's the best
course of action here?

+  bool HandleMouseEvent(const blink::WebMouseEvent& event);
+  bool HandleMouseWheelEvent(const blink::WebMouseWheelEvent& event);
+  bool HandleKeyboardEvent(const NativeWebKeyboardEvent& event);
+
+  // Returns |true| if the event ack was consumed.

[jdduke (slow), 2014/04/04 16:11:28]

Also note here that the consumed ack should not propagate any further (that may
sound implicit, but it can't hurt).

[dgozman, 2014/04/07 16:54:55]

Done.

+  bool HandleTouchEventAck(InputEventAckState ack_result);
+
+  // Cancel any touches, for example, when focus is lost.
+  void CancelTouch();
+
+ private:
+  // ui::GestureProviderClient implementation.
+  virtual void OnGestureEvent(const ui::GestureEventData& gesture) OVERRIDE;
+
+  void InitCursorFromResource(WebCursor* cursor, int resource_id);
+  void UpdateCursor();
+  bool UpdateShiftPressed(bool shift_pressed);
+
+  // Whether we should convert scroll into pinches.

[jdduke (slow), 2014/04/04 16:11:28]

scroll -> scrolls

[dgozman, 2014/04/07 16:54:55]

Done.

+  bool InPinchGestureMode() const;
+
+  bool FillTouchEventAndPoint(const blink::WebMouseEvent& mouse_event);
+  void FillPinchEvent(const blink::WebInputEvent& event);
+
+  // The following methods generate and pass gesture events to the renderer.
+  void PinchBegin(const blink::WebGestureEvent& event);
+  void PinchUpdate(const blink::WebGestureEvent& event);
+  void PinchEnd(const blink::WebGestureEvent& event);
+  void ScrollEnd(const blink::WebGestureEvent& event);
+
+  RenderWidgetHostImpl* const host_;
+  ui::FilteredGestureProvider gesture_provider_;
+
+  // While emulation is on, default cursor is touch. Pressing shift changes
+  // cursor to the pinch one.
+  WebCursor touch_cursor_;
+  WebCursor pinch_cursor_;
+
+  bool mouse_pressed_;
+  bool shift_pressed_;
+
+  blink::WebTouchEvent touch_event_;
+  bool touch_active_;
+
+  // Whether scroll gesture has started but not yet finished. We should
+  // manually finish scroll when emulation is turned off.
+  bool scroll_gesture_active_;
+
+  blink::WebGestureEvent pinch_event_;
+  // Point which does not move while pinch-zooming.
+  gfx::Point pinch_anchor_;
+  // The cumulative scale change from the start of pinch gesture.
+  float pinch_scale_;
+  bool pinch_gesture_active_;
+
+  DISALLOW_COPY_AND_ASSIGN(TouchEmulator);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EMULATOR_H_